VG Smogging issues.

[Wonderingraven]

I am having a bit of troubles here.

I am really stumped, How can I fix this? could the z31 ecu and 86 z31 maf cause this?

[silverton]

High HC is generally an indication of a bad cat.

[Ju_S12_Turbo]

I passed CA smog with the z31 combo

[Wonderingraven]

Yeah, I am going to rule out Vacuum issues. Check the spark plugs.
Cat is good, O2 sensor is good.

[StephenG]

Did you warm it up really good before you went? Just driving a few blocks will not heat your cat up enough to work well.

[Wonderingraven]

I drove it 30 minutes in the heat of the day, with launching at almost every stop light before I got there.  From work to the place of smog, still a failure.
Today's high is 104, and with some high humidity.

[silverton]

Seriously.  high HC is a non-functioning cat.

http://www.smogtips.com/failed-high-hydrocarbons-HC.cfm

I been around the block two or three times.  Listen.
Post Merge

I drove it 30 minutes in the heat of the day, with launching at almost every stop light before I got there.  From work to the place of smog, still a failure.
Today's high is 104, and with some high humidity.

seriously?  launching it?  just drive it like a car on the street dude.  that's just gonna shove a bunch of raw fuel through the cat and make it perform even worse, if it already doesn't perform at all!  A freeway cruise (speed limit) for 5-10 minutes is the best way to make a catalytic converter work at its highest potential.

[Maxpow]

Yeah wot is going to put unburned fuel in there. I get pretty obsessive about warming up the cat so I do about 30 minutes to an hour of driving before dropping it off.

[Wonderingraven]

Cat is good btw, replace plugs, cap, and rotor and it still failed smog.
old plugs wasn't burned or anything and it shows the ignition was clean.

PCV Valve was clogged, so replaced it. changed the fuel filter. 
Next I also tore apart my intake cleaned the throttlebody, and found the lead from the intake to the automatic transmission vacuum line was not plugged at all.  So bingo found my vacuum leak.
Wont know if this did or does anything to help with the smog issues until tomorrow.  Checked for any other vacuum leaks and found none.

Took a drive tonight on the 215 beltway around vegas and it is very responsive now then it ever has been, not launching it or anything and didn't have to clutch kick it to pick speed back up on the 215 when I have to slow down and down shift.  It responds fast, it moves fast, and hopefully now it should pass.

All I can do now is hope this did it, because I am kinda stumped now of what it might and can be. Idle is around 700 - 800, I got this today.
Idle Speed CO  2.44% Greater than 1.20%
High Speed CO 3.54% greater than 1.20%
Idle Speed HC 286 great than 220 parts per million.

No smoke, no gas dripping. No emission smelling either.
But I guess my roomy's notice when I take off it puffs but after all the crap tonight not 1 puff, not even 1 smell from the exhaust pipe.

[rednucleus]

I will be surprised if it doesn't pass with flying colors now. PCV valve & vacuum leak make a big emissions difference. Good job finding those two.

[silverton]

Good luck!

[Wonderingraven]

Even with everything done so far it still failed.

Something I didn't know but I had to close up the screw on the 86 z31 MAF, and did alot of turning and fine tuning to get the numbers low.  With this tuned down, it still felt fast and still have to test it on the gas millage but I think my MPG will increase from 10mpg lol.

[Jsvob03]

All Signs point to running rich, and/or misfiring.

Lets assume its not a misfire, as you say it runs 'fast'.

Rich. basically, the computer is supplying more fuel than is needed to maintain proper a/f ratio. there are 2 main reasons for a car to be running undesirably rich.
1.) The ECU thinks the car is running lean.
2.) Faulty component causing misfires.

Unfortunately for you, #1 is the most common. Finding it, on a pre-obdII car (lol. the s12 is like obd 0.5) is a bit troublesome. Getting data..well...you gotta go get it. I can provide some things to check, it may or may not help.
-Exhaust leaks, especially closer to the Oxygen sensor. (manifold, ypipe)
-Intake/vacuum leaks. use propane as a leak finder and listen for rpm changes.
-Stuck OPEN (maybe not fully open, as the car wouldn't run, but partially open). causes inert gas into the intake, and thus causes poor ignition.
-dirty air filter?
-leaking fuel pressure regulator
-Faulty MAF? you said its a z31 setup. If you still have the stock s12 stuff, maybe swap over to that and see how it does.

[Wonderingraven]

stock s12 stuff is broke or I would of swapped it back. 
- leaked FPR - as far as I know, not even. Pulled the vacuum lead for it and no fuel while running
- Spectre Cone is clean as she can be.
- Not stuck open
- fixed all intake / vacuum leaks
- Exhaust leak was fixed a while ago.
- O2 sensor is good.

So with that said, this was all that was needing adjustment as it was getting too much air / fuel mixture. 


When I removed the vacuum leak last night from the old auto trans vacuum lead, the engine defiantly started and sounded smooth this is also including a new PCV Valve.